A known fuser includes a heat roller, an endless belt having lubricant on its inner circumferential surface, a nip forming member, and a sliding sheet. The nip forming member and the heat roller sandwich an endless belt therebetween to form a nip portion. The sliding sheet is disposed between a portion of an inner circumferential surface of the endless belt and the nip forming member. The sliding sheet has a surface that contacts a portion of the inner circumferential surface of the endless belt. The surface of the sliding sheet has a plurality of dimples for reducing sliding resistance occurring between the surface of the sliding sheet and the endless belt during rotation of the endless belt.